>> reporter: the family attorney -- >> that's how we know that we're dealing with a monster, a hannibal lecter, someone who's very bright and very calculating and very patient. >> reporter: in april, police find the remains of up to six more victims. they speculate about something truly horrifying. there may be more than one serial killer at work here. >> certainly the medical examiner is going to be looking at the possibility that shannon gilbert is one of the remains. >> there is no secret that we've been dumping bodies out here for decades. >> reporter: lou colombo is a retired officer from long island. he shows us how hard it is to search here. >> you can just look at it and know you literally cannot walk in from the roadway into this area. as a result, it lends itself to discarding a body, making it almost impossible to find. >> reporter: he says police have always known the area as a good place to get rid of a body and he explains why this will be a tough case to crack. in all fairness to nasa county police department, there aren't really hard and fast clues here, right? >> nothin